Doonkelberry cake is one of Heinz Doofenshmirtz's favorite kinds of birthday cake. He would always have one in his birthday parties.
- Dr. Doofenshmirtz also uses its cake mix to trap Perry the Platypus in "Raging Bully".
- Dr. Doofenshmirtz explains to Perry the Platypus that ever since he was young, he loved Doonkelberry Cake.
- Doonkelberry bats will swarm anyone with this cake if uncovered.